FIG. 6 provides a schematic front view of a false twister in a conventional false twist texturing machine for producing a doubled yarn. The example apparatus shown has a tension control system in the false twist texturing machine, which combines a Z-twisted filament yarn y1 and an S-twisted filament yarn y2 to manufacture a single SZ doubled yarn y. A single tension detector C detects the tension of the SZ doubled yarn formed by combining the Z-twisted filament yarn y1 and the S-twisted filament yarn y2 to adjust the contact pressure between a disc member D and false twisting belt members B1 and B2, which together constitute an SZ simultaneous false twister T.
In the tension control system in the conventional false twist texturing machine; the single tension detector C detects the tension of the SZ doubled yarn to adjust the contact pressure between the disc member D and the false twisting belt members B1 and B2 via a controller so that the detected tension value has a target tension value or falls within an allowable tension range. Thus, since this system does not individually adjust the contact pressure of the false twister T based on the difference in tension between the Z-twisted filament yarn y1 and the S-twisted filament yarn y2, the quality of the SZ doubled yarn y is limited to a certain level and high quality SZ doubled yarn y cannot be manufactured.
In addition, if the material and thickness of the Z- and S- twisted filament yarns y1 and y2 vary, their tensions must be controlled to appropriate values depending on their material and thickness. The conventional false twist texturing machine, however, cannot perform this function.
It is an object of this invention to solve the problem of the tension control system in the conventional false twist texturing machine for producing a doubled yarn.